The European Commission has approved a combination HIV therapy from Gilead Sciences that is tipped to become another antiviral blockbuster for the firm.
Called Descovy, the drug is a new version of Gilead’s $3.5bn-a-year Truvada (emtricitabine and tenofovir disoproxil fumarate or TDF) that replaces the TDF component with a new salt called tenofovir alafenamide (TAF).
The new compound has around 10 times the potency of TDF and as a result can be dosed much more sparingly, avoiding some of the side effects of its parent.
Clinical trials have shown that TAF is safer than TDF in terms of renal toxicity and bone demineralisation, to recognised toxicities associated with the original drug.
Gilead is in the process of replacing all its TDF-based HIV drugs with TAF alternatives. Descovy was approved by the US FDA earlier this month, while a three-drug combination called Odefsey (emtricitabine, rilpivirine and TAF) – a follow-up to its $1.4bn Complera product – was given the green light in the US last month.
Four-drug product Genvoya (elvitegravir, emtricitabine, cobicistat and TAF) was approved in its first markets last year and is positioned to replace Gilead’s $1.8bn Stribild brand.
Descovy is considered the most important new product commercially however as it is widely used in HIV patients, while three- and four-drug products tend to be reserved for patients starting out on therapy with no drug resistance.
With follow-ups to its three TDF-based products now approved, Gilead is positioned to protect its HIV franchise from competitors, most notably ViiV Healthcare, which has been gaining ground in the HIV category.
ViiV – a joint venture between GlaxoSmithKline (GSK), Pfizer and Shionogi – has been making headway in the market with its Triumeq (abacavir, lamivudine and dolutegravir) and Tivicay (dolutegravir) brands, which have been growing strongly and reportedly taking market share from Gilead.
Sales of Triumeq and Tivicay reached £1.3bn ($1.9bn) last year and the two drugs are predicted to hit almost £5bn by 2020, according to analysts at UBS.
Gilead is not lying down however. In addition rolling out its TAF-based drugs, the company is also conducting a head-to-head clinical trial of a single-tablet combination of TAF, emtricitabine and an experimental drug codenamed GS-9883 in the hopes that it will show a clinical advantage over Triumeq.